It is difficult, often meaningless to try to figure out where the person ends and the technology starts. The boundaries one has for experiencing the world go beyond the physical limitations of his/her skin and are determined by the system for experiencing the world in which he/she exist. In his book, Steps to an Ecology of Mind, the cybernetics pioneer Gregory Bateson illustrates this point with the example of a blind man with a walking stick. In her book, The War of Desire and Technology at the Close of the Mechanical Age, Allucquere Roseanne Stone describes her feelings after attending a lecture given by the physicist, Stephen Hawking. Stone starts off listening to Hawking outside the overcrowded auditorium through the Public Audio system (PA), but decides she wants to go in and see and listen to him in person. Hernwall uses the concept "cyborg" when considering a human being with his or her technology as a functional unit.